Background: Roquinimex is being used for posttransplantation immunotherapy of autologous bone marrow transplantation for acute and chronic myelogenous leukemia. This immunotherapeutic agent is a cytokine inducer and may induce an autologous graft-versus-host (GVH) and graft-versus-tumor reaction. Objective: Our purpose was to examine patients undergoing this immunotherapy for clinical signs and symptoms of acute GVH reactions and to correlate these symptoms with their clinical outcome. Methods: We studied eight patients receiving roquinimex therapy. Results: We found autologous GVH reactions in three of eight patients (38%) treated with this immunotherapy. Their disease was manifested by localized or widespread violaceous papules that on histologic evaluation were compatible with a grade II GVH reaction. The acute cutaneous GVH reaction was associated with eccrine sweat gland necrosis, a dermatologic toxicity usually associated with chemotherapy. Conclusion: Long-term studies of larger numbers of patients treated with this immunotherapy will determine whether these GVH reactions confer significant, sustained, antitumor effects.